Meaning of the Sanskrit Word: jyotisam

  jyotiṣām—of all luminaries    Bg 10.21
  jyotiṣām—in all luminous objects    Bg 13.18
  jyotiṣām—by luminaries    SB 4.9.20-21
  jyotiṣām—of luminaries    SB 4.12.39
  jyotiṣām—of the luminaries    SB 5.16.1
  jyotiṣām—of the sun and other luminaries    SB 6.1.4-5
  jyotiṣām—of the luminaries like the sun and moon    SB 6.12.33
  jyotiṣām—of all the luminaries    SB 9.5.3
  jyotiṣām—knowledge of astrology (along with other aspects of culture in human society, and specifically in civilized society, there must be knowledge of astrology)    SB 10.8.5

Can't find any compound Sanskrit words containing jyotisam.